Multiple electronic circuits are formed in a semiconductor device mounted in an electronic element. As a non-contact inspection method of inspecting a broken wiring line or the like occurring during the manufacture of the electronic circuits in a non-contact manner, there is a known method, which is disclosed in Patent Document 1, for example, of inspecting a defective PN junction, a broken wiring line, a short-circuit, or a high resistant portion.
As shown in FIG. 13, the known non-contact inspection method is performed by irradiating a pulse laser beam 110 to a P-type diffusion region 101, an N-type diffusion region 102, constituting an MOS transistor or the like, or a built-in electric field generation portion such as a metal semiconductor interface which is disposed in a semiconductor device provided on a stage 108 to detect an electromagnetic wave radiated toward free space. Reference Numeral 103 denotes a board. Reference Numeral 104 denotes an insulating film. Reference Numerals 105, 106, and 107 denote wiring lines.
A defect diagnosis of the semiconductor device is performed by detecting the electromagnetic wave radiated from the pulse laser irradiated position in this way, converting the detected electromagnetic wave into a time-varying voltage signal corresponding to a time waveform of an electric field amplitude of the electromagnetic wave, and detecting electric filed distribution in the semiconductor device.
Specifically, in a step S1 shown in FIG. 14, an amplitude waveform of an electromagnetic wave radiated toward free space is acquired by irradiating a pulse laser beam to a predetermined inspection region of an inspection target.
In a step S2, a quality determination is made by comparing the amplitude waveform of the electromagnetic wave acquired in the step S1 with an amplitude waveform which has been measured and acquired in advance and radiated from the predetermined inspection region in a non-defective device.
FIG. 15 shows an amplitude waveform of an electromagnetic wave generated when irradiating a pulse laser beam to a semiconductor circuit. On the assumption that the amplitude waveform shown in FIG. 15 is an amplitude waveform of an electromagnetic wave generated from a predetermined inspection position in a non-defective device, the quality of a semiconductor device is determined by comparing a maximum value V of the amplitude waveform of the electromagnetic wave at time T, for example, with the maximum value of an amplitude waveform generated from the predetermined inspection region of the semiconductor device as an inspection target.
A criterion for the quality determination varies with inspection items. Since the maximum value or the minimum value of an amplitude waveform of an electromagnetic wave varies with a difference in the structure of a pulse laser beam irradiated position in many cases, the maximum value or the minimum value of the amplitude waveform of the electromagnetic wave is compared. When the maximum value or the minimum value is different from that of a reference device, it is determined that a semiconductor device having the value as an inspection target has a defect.
Patent Document 1: JP-A-2006-24774